Most liked posts in thread: Guys, there be a DRAGON in that there CAVE(!)

Something I've just come to realise is that the expansion connector matches that of the Co-Co, as the SDC cart only needs an option switch to be set to use in a Dragon. I assume most upgrades can do the same.

It's also possible to stack PIA's and play with the ‘Chip Enable’ lines and an additional address line to add this.

Would work in a very similar way as the Atari version.

 

Yeah someone is selling a CoCoSD cart on feeBay for CoCo’s and Dragons so the cartridge port must be identical or near identical with a couple of dip switches to change track assignments. Cannot find a schematic for the PCB though....
Not yet anyway

 

The Dragon emulator “Xroar” is very good and I have a Dragon 64 with DragonDos cartridge as my default setup so running OS9 level 2 is possible, I think.
I have a Raspberry Pi ZeroW working as a CoPro on my Beeb and one of the cores is a 6809 Co-Processor that lets you run Flex/OS9 to but I haven’t really got into that much.
I have some Raspberry Pi level shifter board on the way if anyone has a Beeb and wants in on the Co-Pro party just let me know. I also have some CPC Single MX4 adaptors on the way which let you plug in a MX4 expansion and has a pass through edge connector as well. I used to use one to plug in my 512KB RAM expansion when using SYMBOS I have 10 PCB’s coming in Matt Black. If anyone wants one drop me a line the rest will be listed on the sell my retro website to fund further Dragon expansions

 

The Dragon uses 6821 PIA’s and I have found a spare one in my parts box, I remember seeing 6821’s ( the 2mhz version ) being used as replacements for the Atari but I’m not sure what needed two PIA’s stacked on top of each other.

 

IDRIS is most definitely on her way, Richie. After the CO-OP's lack of courier labels on Monday, she was dropped off Monday night and will have left Hull yesterday morning, mate.

You'll know when she's arrived with you there...



So ensure you have your sprinklers set to the....

MAX!

 

Hi Richie
If you can get hold of a decent schematic, I'm happy to help you with a small circuit to add an additional PIA chip.
I've just found among the lost Items, the original instructions for the C.U.P.I.D. Centronics Printer port upgrade.
and guess what? uses a recomemded 6821 sat on top of the 6522, all the Power Address and Data lines soldered directly, and most of the control lines Bar Chip select. all PORT A & B plus CA0,1 CB0,1 left out to connect what ever you choose.
In this case the additional Chip Select line connected to the O.S. Controller at one of either D1xx,D5xx,D6xx or D7xx but as not in front of me can't tell you which.

It would be nice to see some close up internal shots of the Dragon maybe four photo's to cover the whole board at High Resolution.

 

Idris the Dragon has landed!

 

All downloaded... So how is the firey beast ?
P.S are the PIA's in sockets ? what revision board, 16 Memory sockets, 8 etc etc.

Yea I'm excited for you !!

 

Hey Andy, what weird discoveries can be made while restructuring the Baz Towers... There in the higher tower of the castle where the princess was asleep guarded by a ferocious dragon with 32 sharp teeth, ready to snap and eat you all out, the bold and stainless knight called Sir Barr managed to kill the princess at last... and save the Dragon!!

Nice to see you back here,mate. And yes, I'm definitely interested in the d32 lot, if still available.

 

I don't think that the Dragon 64 was any great quantum leap, Graham, other than that extra 32Kb of RAM.

Here we go, for anyone else interested in the story of this scaly, much-rumoured beast:



and

 

Hi, Graham.

Yes, powered by some fiendish 6809 processor, the Dragon is certainly..."different".
All it needs next is a set of those amazing (Radio Ham?) aerials of yours (incredible!) plugging into the joystick ports (also non-standard) and this beast would probably be able to FLY to the moon and back!
Yes, the time available for computing and hobbyist activities has been little of late as we're either at work, home unwinding/going for a walk to escape the building site or...sleeping! Weekends start at 6am to catch the NHS shopping hour to beat the queues and so we're usually absolutely knackered after 6 early starts out of a full-on week so bed's calling and then you begin the same old routine over again... it's been an exhausting cycle of late, mate.

Any road, it sounds like you've got some groovy projects on the go/back burner there with the PokeyMAX/XEGS, 6502 assembler and those old DOS/Win 3.1 disks to delve through...it's all happening and why not? Your Cellnet programming days deserve a thread all of their own, Graham, and I'm sure we will see some progress with the old Microdisc in a thread to appear shortly...hand on heart, it's still all in its bubblewrap to protect it from plaster dust and rubble! (It also serves as a camouflage so that Bev doesn't realise it's 80s technology and hopefully thinks it's part of her new kitchen units!!)

Hey, talking of old units, the old fire-breathing DRAGON 32 beast is still available if anyone can (at the very least) match the £80 I paid for the machine and the basic set-up. As I said, I've since spent another £20-30 on extra games tapes, mags etc but I might take a bit of a hit there just for the sake of a sale and giving someone else a "buzz" out of checking out such a strange and exotic micro. Let me know, guys, via a PM else it's on Feebay next week.

OK, toodle pip and catch you fellas again soon - btw, I dropped Beamer320 a note last night and requested his presence on the good ship Atari Owner...we will see if Dom joins us...?

 

Had to delete what appeared as a double post sorry about that thought I was editing it
Had to correct text I wasn't by far the only engineer, just the only support engineer for the U.K.(the rest managers) (although I never went to Northern Ireland, I was due to go to Enniskillen, but someone decided to remove the front of a hotel with a car bomb, so my visit was cancelled)

The Welsh Wonder :
I got to admit the Dragon is green... even the black was a very dark you guessed GREEN well apparently, but the links made interesting viewing so Thank You !!

Oh and Hermes did deliver Richie's 1050.. complete with a crack in the PSU casing, so god knows what they did with the parcel, as I'd though I'd protected it well enough with bubble wrap and additional cardboard .. I'll sort out something to make sure he's a happy bunny. Get Well soon Richie.

 

I would like to take you up on the Dragon Andy but I have no more space for any extra Retro kit.

 

I'm in the same boat, to much kit and not enough inclination at the moment.

In regard bouncing signals off of the moon, It was possible to measure distance yes as a noticeable delay in the reflected signal, from memory 2 to 3 seconds, also the frequency we transmitted on would be changed by Doppler effect due to relative movement between the earth and the moon, so usually used a spectrograph to watch for any return signal.

Only reason for trying it was because we could, A special licence required as power was very much higher than an amateur licence allowed. It was the technical and practical difficulties to overcome that made it interesting, building a monster RF power amplifier; the; I’ll call in plumbing to the antenna system, building the array, generator power supply, Making sure the farmer was happy about taking over one of his fields for three months etc.etc.

And the back up from others across the world in trying to receive our transmission..

After all if we transmitted, anyone that could see the moon could receive, so approximately 49% of earth. Our station was using CW (carrier wave) modulation, Morse code, sent from a ZX spectrum, rather than by hand. Frequency in the 2M Amateur band approx. 145MHz

As I'm sure you will gather there were more than just myself, there being three of us building the ground station and equipment; that taking about 2 years but, peeps all over the world looking out for the signals return. Not something easy to
Orchestrate 25 years ago.

https://www.electronics-notes.com/a...ur-propagation/moonbounce-propagation-eme.php

 

That sounds like a lot of fun and the little Spectrum at the heart of it. How did you interface the Speccy? I think we need a blog on this

 

@Andy Barr , Those controllers look horrid! I remember playing with Apple analog joysticks and I owned a Kraft of similar design for my Atari for a short time (I think I just threw it away), and I hated the feel of loose sticks. The Odyssey 2 console has similar sticks as well, and yes, they are terrible too, to me. But then with your Dragon controllers they have to throw in some weird and very uncomfortable "handle" with the button in the worse possible spot! Were they actively attempting to make their games terrible to play? Thank God you don't have to use them and have that joystick adapter! IIRC, RS/Tandy Coco's also have similar 1st party controllers and they need 3rd party joysticks or adapters to properly play games as well.

 

OO So were to I start .. Number 3
Andy Barr
Joysticks , well at least analogue joysticks.. Well there only going to be any good under three conditions being met.
1: The analogue to Digital conversion itsef ... witness BBC's Port . Three cheap diodes in series a resister to +5V and a capacitor across the diodes to ground, all used as a 1.8V referance for A to D conversion ... not terriably good.
2: The pots used in the joysticks, the 'throw' the joystick uses is a very small bit of the full travel of the 'Pot' or variable restistor used i.e rotation something like 330 Degrees, however in a joystick down to maybe 70 degrees. Cheap pots arent very 'linear'
Expensive ones can be used if you want to pay for them maybe those by Bournes.
3: The physical build of the joystick, it's drag or feel, and it's mechanical integrity. any slop at all results in differences to the movement on screen.
Interesting link !!

 

I hear you on that one Matt

Although I've not searched high and low there may be an FPGA source for the unavailable GIME Chip.
In which case it's not so bad spending on something at $600 this is of course if you have that kind of money.
in some way it looks like the Dragon64 is a little better than the CO-CO 2 just a matter of sorting out the O.S. software and in effect having the best of both worlds. Dragon64 and Co-Co 1&2 compatibility as well.
I know the 6809 was considered as a very good 8 Bit CPU and some of the internal functionality going towards 16 bit.
Kind of the reverse of the 68000 design having 8 bits ripped off and calling it a 68008 for the QL as an example.

https://www.ebay.co.uk/itm/Radio-Sh...738218?hash=item46b2753bea:g:QFUAAOSwbHRfJ8jD

This is the only current listing on Ebay UK however a fair number from the U.S. and Canada
It wouldn't be to terrible a job to change the internal transformer to one that accepted 240V may even be able to change some strapping on the transformer.

It's something I'll not consider for some time. but who knows.

By and By I've found a way of getting the cables through to the Atari 800 PCB slots without any cutting of the Atari itself, just removing one of the bumps sticking down next to the left hand side (when looking from keyboard) of the incognito. Allows a gap above the socket right at the very end and the plastic PCB and cart guide to place all cables and a 'twisted & folded' ribbon from the 74LS42 I've only been playing as I'd taken out the guts when I received the incognito just haven’t been to bothered to do anything..

 

There’s another working Co-Co 2 on feeBay... £200 quid though

https://www.ebay.co.uk/itm/254681184950

 

Is relocating to Chez Farrell

 

I wish I still had my Dragon 64 ... along with my Camputers Lynx96 and MGT Sam Coupe. Sadly I sold a lot of my collection to buy a Amiga A1200 which was more important at the time. Plus so of my kit was stolen in a burglary so I was letting the other stuff go. My old Atari setup was cracking, Dual 1050’s, 800XL and a 1027 printer....

 

Hmm well there doesn’t appear to have an emoji for putting your foot in it

 

Yes the Genlock was a good USP for Amigas I always my mate telling me that they used A1200’s to make the fx for Babylon 5. I know now it was heavily upgraded 4000’s with some top-end Video Toaster software.
I fitted a HDD to my A1200, I think it was a 70MB drive and cost £90 in ‘93 ... not cheap, but being able to boot Workbench 3.1 off a HD felt like it was instant.

 

I've no idea for mine, I suspect it was a drive I got from work and the bits I purchaed were the proper cable and mount to go inside.
I wish I remember more, but until I found the books and reciept I didn't even recall having an Amiga. least its jogged some memories now.
I found two of my TV transmitters and one reciever as well. I remember selling the power amplifier I'd built, too build one again is a small fortune as well (And thats just the exotic components)

Also found some pictures of the portable pump up mast and Generator trailer I'd help build.